一种分析LC振荡器的简便方法

提出把LC振荡器等效成负阻振荡器的新观点，并以电容三点式振荡器为例，利用物理概念导出了该振荡器的振荡条件和振荡频率的准确公式，并将结果与相关讨论进行比较。由此推断：所有LC振荡器均可等效为负阻振荡器，从而可方便得到振荡条件和振荡频率。该方法的特点是物理概念清晰，数学过程简便。     

Organizational climate, services, and outcomes in child welfare systems

Objective

This study examines the association of organizational climate, casework services, and youth outcomes in child welfare systems. Building on preliminary findings linking organizational climate to youth outcomes over a 3-year follow-up period, the current study extends the follow-up period to 7 years and tests main, moderating and mediating effects of organizational climate and casework services on outcomes.

Methods

The study applies hierarchical linear models (HLMs) analyses to all 5 waves of the National Survey of Child and Adolescent Well-being (NSCAW) with a US nationwide sample of 1,678 maltreated youth aged 4–16 years and 1,696 caseworkers from 88 child welfare systems. Organizational climate is assessed on 2 dimensions, Engagement and Stress, with scales from the well established measure, Organizational Social Context (OSC); youth outcomes are measured as problems in psychosocial functioning with the Child Behavior Checklist (CBCL); and casework services are assessed with original scales developed for the study and completed by the maltreated youths’ primary caregivers and caseworkers.

Results

Maltreated youth served by child welfare systems with more engaged organizational climates have significantly better outcomes. Moreover, the quantity and quality of casework services neither mediate nor interact with the effects of organizational climate on youth outcomes.

Conclusions

Organizational climate is associated with youth outcomes in child welfare systems, but a better understanding is needed of the mechanisms that link organizational climate to outcomes. In addition, there is a need for evidence-based organizational interventions that can improve the organizational climates and effectiveness of child welfare systems.     

FBIS族：美国政府与决策智囊对外政策的重要信息源

梳理了美国FBIS机构及其产品的发展历程,介绍了FBIS族的获取途径及其针对中国进行媒体监测的情况,分析了FBIS族的主要特点,并指出其对我国的启示。     

多系统平台协作电子音乐系统研究与实现

计算机技术的发展，为电子音乐的创作与实现提供了基本保障，并且为电子音乐的发展提供了更多的可能性。随着软硬件系统的发展，利用多种不同软硬件平台的协作，共同完成电子音乐创作与实践也就成为一种可能。通过对相关要素的梳理，为构建多系统平台协作的电子音乐系统提供理论和实践的分析与支撑。